arkady151

iTrader: (15)

I have a stock port s4 t2, apparently recently rebuilt, good running motor. A friend offered me a 62-1 plus a mani and all the fuel system stuff for cheap. At first I thought it was a 60-1 which would have been a good turbo for making 350whp. As thats what I would like to make since the s4 rear iron seems to crack over 400whp or so they say. Regardless I think 350whp will be plenty fun in a t2 vert. But the turbo ended up being a 62-1 which is bigger , now I've searched this subforum on what people have made on the 62-1 and it seems like its a good turbo for 400-450. Thus I'm thinking its too much for my needs regardless of how good of a deal it is.

So my question is should I bother with a 62-1 for 350whp, or will it be too laggy, the turbo has a .81 hot side from what I know. Or should I just get a bnr hybrid and not bother with going with a big-ish single for such a small power goal.

arghx

iTrader: (3)

post good pics of the manifold and turbo.

Sesshoumaru

iTrader: (1)

I think you will like the turbo.

at a P/R of 1.8 ~ 12psi your looking at about 45lbs/min for your engine.

that's about 350rwhp and should be about right for your car (7k rpm with VE of 1.1 for non-SP)

It will be a fun turbo with a .81 and shouldn't be laggy at all as it's a mid sized turbo (62mm wheel).

I have a BB 62-1 on a stock port (mostly) FD motor with the 1.00 divided and spools pretty well.

I just bought the .84 divided so will try that out.

Your .81 is undivided and more than likely your manifold is divided. Not the best setup as it's a bit small and you dont' get the divided benefit.

(I attached pics of mine on a HKS log manifold)

arghx

iTrader: (3)

Without seeing pics the .81 is most likely an on-center undivided housing and the manifold is probably an ebay log manifold. Don't expect good transient response with that setup. I had a .96 undivided tangential 60-1 on an FC HKS log manifold and it was pretty unresponsive around town.

arkady151

iTrader: (15)

Its an HKS manifold. Almost positive the same one as listed above. No idea about the other specs really, need to stop by the friends house and look it all over again and take pics as said.

I'm definitely looking for more so response over power. My 335 makes 350whp/370wtq right now, and its definitely fun, the powerbands are obviously way different as the 335i has a shitload of torque because of its babydick turbos but falls on its face up top. I figured a car that weighs 700lb less with the same power will be even more fun. As long as it starts spooling around 3ish and makes full boost around 4 and holds that till redline then I will be a happy camper.

I'm just worried it will be like an on/off switch , lag lag lag, powaaaaaa. Maybe I'm over analyzing it and thinking the turbo is bigger than it really is, its been a while since I had a turbo 7 so I forgot a lot lol.

Thus the question of if I should pass this deal up and just get a BNR hybrid.
Lets say its the HKS Log mani, undevided housing, .81 hot side. Theoretically speaking where would it spool.

arghx

iTrader: (3)

from my experience, log manifold + T4 undivided turbine housing is most noticeable when you are on the highway in 5th gear. Talk about dead. It feels like a non turbo 6 port engine with the aux ports wired open.

I was just in a brand new 335 with manual transmission this past weekend. What you are looking at is going to be completely opposite of a 335. Divided manifold + divided turbine housing makes an even larger bigger difference on rotaries due to the exhaust port area and strong exhaust port pulsing effects.



If you are on a budget you might want to consider a BNR stage 2 (s5 version with the OEM twinscroll). See this thread on Mazda's testing of single scroll vs twin scroll on a rotary https://www.rx7club.com/single-turbo-rx-7s-23/mazda-scientifically-tests-single-scroll-vs-twin-scroll-turbos-903210/

Sesshoumaru

iTrader: (1)

From my experience I reached full boost (1 bar) approximately 3600-3800rpm.

This was on WG spring and the 1.00 divided (WG would start to open around 6psi).

With a EBC and smaller A/R I would like to reach 1 bar at around 3300-3500rpm.

On center is not ideal as it's a bit more inefficient and might not even fit on the manifold.

A new turbine housing is about 250 bucks if you wanted to go a different route.

The biggest thing I would be concerend to check if it's the BB version or JB.

You can look through the oil drain to tell if it's the BB verion.

diabolical1

iTrader: (3)

i wish i had your problems.

get it. it will take some time and effort to work out the details of setting it up the way you want, but it can be done.

arghx

iTrader: (3)

if you start running the numbers, it's not such a good deal to get this turbo versus a brand new hybrid that may be more responsive. you will have to buy a wastegate and adapt it to work to the HKS flange (don't just bolt on an HKS 40mm b/c you will get creep). you will need custom oil lines. you will need a custom downpipe. If noise is a concern you will need to recirculate the wastegate. You will need to re-work your intercooler piping more than if you got a bolt-on turbo. You could have all sorts of fitment issues to deal with such as the factory clutch fan (if still equipped).

arkady151

iTrader: (15)

Thats what I'm thinking too, not to mention I have many other areas to focus on the car. The setup does come with an HKS wastegate like you mentioned lol. Its has all the lines, I'd need a fitting or two. But regardless yeah I think I'll just get a BNR hybrid down the road. As this option was more so of something that popped up. I figured I'd consider it , if it was something that was good for my goals but it seems like more so of a hassle and I've honestly only had the car for a few months and still need to go over many other aspects, so stock turbo for now is the plan, and I'll do the BNR hybrid later on down the line. Thanks for all the help and all the information though.

FrankV702

iTrader: (14)

What is he selling the turbo for?? I'd love to try out a 62-1. I had one a while back but sold it before I got a chance to run it on my car.

arkady151

iTrader: (15)

I'll ask him to throw up a for sale thread for it,